A laboratory-field study to better define those properties of granular base materials which significantly contribute to the resilient response of pavement structures under repetitive loadings has been conducted. Results of the laboratory study, previously reported by the authors, indicated that the stress deformation properties of granular materials, when measured in repeated load triaxial compression, are non-linear with their modulus values and Poisson's ratios dependent on stress state to a considerable degree. Field studies included measurements of the response of a prototype pavement, 20 ft. by 20 ft. in plan, to repeated-load plate tests and of an in-service pavement in San Diego County, California to an actual truck load. Both pavements consisted of an asphalt concrete surface, a granular base course, and a clay subgrade. Instruments were placed at various positions in the pavement structures to measure deflections, stresses and strains. For the prototype pavement, the plate load tests were conducted at the pavement surface with the base course in both a partially saturated and saturated state. Loads were applied through rigid plates at durations representative of moving traffic and in sufficient numbers to assure that a reasonable measure of the resilient behavior could be obtained. These responses were then compared with computed values which were obtained from three different non-linear elastic analyses and laboratory determined stress-strain properties. The results indicated that the predicted stresses, strains and displacements compared reasonably well with field measurements; the responses yielded by the different numerical methods were similar; and the resilient responses of the system were only slightly affected by degree of saturation of the base course. The approach developed to predict pavement responses for the prototype pavement was extended to a full-scale test road in San Diego County, California, to verify its application to conditions representative of moving traffic on highways. Measurements of strains and displacements were obtained under a slow moving truck and compared with predicted Values. As with the prototype pavement, results of the analyses indicated that the predicted and measured responses were in good agreement. /AUTHOR/

Supplemental Notes:

Presented at the Third International Conference on the Structural Design of Asphalt Pavements, Grosvenor House, Park Lane, London, England, Sept. 11-15, 1972.

Corporate Authors:

International Conf Struct Design Asph Pvmts (3rd)

University of Michigan, Department of Civil EngineeringAnn Arbor, MI
United States
48104

International Conf Struct Design Asph Pvmts (3rd)

University of Michigan, Department of Divil EngineeringAnn Arbor, MI
United States
48104

Interrational Conf Struct Design Asph Pvmts (3rd)

University of Michigan, Department of Civil EngineeringAnn Arbor, MI
United States
48104